Cosmetic composition

ABSTRACT

To provide a cosmetic composition having excellent ultraviolet protection against both UVB and UVA, causing neither unpleasant whitening to the applied skin nor skin irritation, and ensuring good feeling on use and high safety and high stability without causing decomposition of the ingredients blended in the cosmetic material, such as organic ultraviolet absorber. A cosmetic composition obtained by using fine particulate titanium oxide and fine particulate zinc oxide each surface-treated with silica, alumina or alumina/silica and having a primary particle size of 0.01 to 0.2 μm in combination and blending titanium oxide and zinc oxide at a mass ratio of 1:4 to 2:3, wherein SPF is maintained as compared with the case where the mass ratio of titanium oxide to zinc oxide is 1:0, and when applied to a thickness of 10 μm, the whiteness W value measured using the CIE color specification system is 20 or less.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit pursuant to 35 U.S.C.§119(e)(1) of U.S. Provisional Application, No. 60/275,466 filed on Mar.14, 2001, pursuant to 35 U.S.C. §111(b).

TECHNICAL FIELD

[0002] The present invention relates to a cosmetic composition,particularly a cosmetic composition having a capability of ultravioletprotection. More specifically, the present invention relates to acosmetic composition capable of providing excellent ultravioletprotection against both ultraviolet B (UVB; radiation having awavelength of 290 to 320 nm) and ultraviolet A (UVA; radiation having awavelength of 320 to 400 nm), causing neither unpleasant whitening tothe applied skin nor skin irritation, and ensuring good feeling on useand high safety and high stability without causing decomposition of theingredients blended in the cosmetic material, such as organicultraviolet absorber.

BACKGROUND ART

[0003] Conventionally, an organic compound-based ultraviolet absorber,an inorganic compound-based ultraviolet-shielding agent or the like isblended in cosmetic compositions having a capability of ultravioletprotection. The organic compound-based ultraviolet absorber now on useincludes 2-ethylhexyl p-methoxycinnamate for UVB protection and4-tert-butyl-4′-methoxydibenzoylmethane for UVA protection. However,when these are blended in a large amount so as to enhance the capabilityof ultraviolet protection, a problem of increase in stickiness or skinirritation arises. Furthermore, 4-tert-butyl-4′-methoxydibenzoylmethaneand the like cannot be stably blended because of their low solubility inan oil agent and coloration due to chelation with metal ion. Inaddition, these UV absorbers are poor in the photostability and theirdecomposition jeopardize the safety.

[0004] On the other hand, with increasing attention to the safety ofcosmetics, use of an inorganic compound-based ultraviolet-shieldingagent is widespread and in particular, titanium oxide and zinc oxide areused for general purposes. However, if titanium oxide is blended in ahigh proportion so as to obtain sufficiently high protection againstultraviolet rays, dry or powdery feeling is generated and when appliedto skin, unpleasant whitening seriously occurs. As compared withtitanium oxide, zinc oxide is low in the capability of ultravioletprotection per unit mass despite its excellent transparency andtherefore, for obtaining sufficiently high ultraviolet protection, zincoxide must be blended in a higher proportion than titanium oxide, as aresult, dry or powdery feeling is generated and moreover,aggregation/gelling takes place due to the elution of zinc ion.

[0005] These inorganic compound-based ultraviolet-shielding agents havephotocatalytic activity and therefore, are surface-treated with silica,alumina or the like, however, the concealing effect is insufficient andother cosmetic base materials including an organic compound-basedultraviolet absorber are decomposed.

[0006] As such, the kind and the blending amount of theultraviolet-protecting agent which can be blended in cosmeticcompositions for preventing sunburn are limited and a fully satisfactoryultraviolet-protecting agent has not been found.

DISCLOSURE OF INVENTION

[0007] On of the objects of the present invention is to provide acosmetic composition having high capability of ultraviolet protectionagainst UVB and UVA, causing neither unpleasant whitening to the appliedskin nor skin irritation, ensuring good feeling on use. One of theobjects of the present invention is to provide a cosmetic compositionhaving high safety and stability while preventing the decomposition ofingredients blended in cosmetics, such as organic ultraviolet absorber.

[0008] As a result of extensive investigations to attain theabove-described objects, the present inventors have found that the soleuse of titanium oxide gives a sufficiently high SPF but cannot besatisfied in preventing the unpleasant whitening and the sole use ofzinc oxide can give neither sufficiently high SPF nor UVB protectioneffect, nevertheless, when particulate titanium oxide and particulatezinc oxide each coated with a certain dense silica film and having aprimary particle size of 0.01 to 0.2 μm are used in combination andblended at a mass ratio of particulate titanium oxide to particulatezinc oxide of 1:4 to 2:3, the obtained cosmetic composition can besynergistically elevated in the ultraviolet protection effect, maintainthe same high SPF of 30 or more as in the sole use of titanium oxide, befree of generation of the unpleasant whitening on the applied skin, beextremely reduced in the skin irritation and ensure excellent feeling onuse and high safety and stability while preventing the decomposition ofingredients blended in cosmetics, such as organic ultraviolet absorber.The present invention has been accomplished based on this finding.

[0009] More specifically, the present invention relates to the followingmatters.

[0010] [1] A cosmetic composition having blended therein silica-,alumina- or alumina/silica-coated particulate titanium oxide andsilica-, alumina- or alumina/silica-coated particulate zinc oxide at amass ratio of 1:4 to 2:3, the particulate titanium oxide and theparticulate zinc oxide each having an average primary particle size of0.01 to 0.2 μm.

[0011] [2] The cosmetic composition as described in [1] above, whichcomprises the silica-, alumina- or alumina/silica-coated particulatetitanium oxide and the silica-, alumina- or alumina/silica-coatedparticulate zinc oxide in total amount of 5 to 25% by mass based on theamount of the cosmetic composition.

[0012] [3] The cosmetic composition as described in [1] or [2] above,which comprises an organic ultraviolet absorber.

[0013] [4] The cosmetic composition as described in [1] or [2] above,which comprises from 2 to 8% by mass of 2-ethylhexyl p-methoxycinnamate.

[0014] [5] The cosmetic composition as described in [1] or [2] above,which comprises from 0.1 to 3% by mass of4-tert-butyl-4′-methoxydibenzoylmethane.

[0015] [6] The cosmetic composition as described in any one of [1] to[5] above, wherein the cosmetic composition maintains the same SPF (SunProtection Factor) value as in the sole use of titanium oxide and whenthe cosmetic composition is applied to a thickness of 10 μm, thewhiteness W value measured using the CIE (International Commission onIllumination) color specification system is 20 or less.

[0016] [7] The cosmetic composition as described in [6] above, whereinthe SPF (Sun Protection Factor) value is 30 or more.

[0017] [8] The cosmetic composition as described in any one of [1] to[7] above, wherein the PFA (Protection Factor of UVA) of the cosmeticcomposition is 4 or more.

[0018] [9] The cosmetic composition as described in any one of [6] to[8] above, wherein the W value is 15 or less.

[0019] [10] The cosmetic composition as described in any one of [1] to[9] above, wherein the particulate titanium oxide and the particulatezinc oxide each is coated with silica and the silica film has athickness of 0.1 to 100 nm.

[0020] [11] The cosmetic composition as described in [10] above, whereinthe surfaces of the silica-coated particulate titanium oxide and zincoxide are further made hydrophobic by using a hydrophobizing agent.

[0021] [12] The cosmetic composition as described in [11] above, whereinthe hydrophobizing agent is one or more selected from the groupconsisting of silicone oils, alkoxysilanes, silane coupling agents, andhigher fatty acid salts.

[0022] [13] The cosmetic composition as described in any one of [10] to[12] above, wherein the silica-coated particulate titanium oxide and thesilica-coated particulate zinc oxide each has a photocatalytic activity,determined by a tetralin auto-oxidation method, of 60 Pa/min or less.

[0023] [14] The cosmetic composition as described in any one of [10] to[13] above, wherein the silica-coated particulate titanium oxide and thesilica-coated particulate zinc oxide each has a dye discoloration rate(ΔABS₄₉₀/hr), determined by a Sunset Yellow method, of 0.1 or less.

[0024] [15] The cosmetic composition as described in any one of [10] to[14] above, wherein the silica-coated particulate titanium oxide and thesilica-coated particulate zinc oxide each has an organic ultravioletabsorber decomposition rate (ΔABS₃₄₀/hr), determined by a Parsol 1789method, of 0.02 or less.

[0025] [16] The cosmetic composition as described in any one of [10] to[15] above, wherein the silica-coated particulate titanium oxide and thesilica-coated particulate zinc oxide each has an organic ultravioletabsorber decomposition percentage, determined by an ethylhexylp-methoxycinnamate method, of 5% or less.

[0026] [17] The cosmetic composition as described in any one of [10] to[16] above, wherein the silica-coated particulate titanium oxide and thesilica-coated particulate zinc oxide each has a kinetic frictioncoefficient, determined by a glass plate method, of 0.550 or less.

[0027] [18] A method for producing a cosmetic composition, comprisingbringing particulate titanium oxide and particulate zinc oxide eachhaving an average primary particle size of 0.01 to 0.2 μm as a mixture(at a mass ratio of 1:4 to 2:3) or separately into contact with a silicafilm-forming composition containing water, an alkali, an organic solventand a silicic acid having neither an organic group nor a halogen or aprecursor capable of producing the silicic acid, with the water/organicsolvent ratio being from 0.1 to 10 and the silicic acid concentrationbeing from 0.0001 to 5 mol/liter, thereby coating the particulatetitanium oxide and the particulate zinc oxide with silica, and dryingand blending these particles.

[0028] [19] The method for producing a cosmetic composition as describedin [18] above, which comprises blending from 2 to 8% by mass of2-ethylhexyl p-methoxycinnamate.

[0029] [20] The method for producing a cosmetic composition as describedin [18] above, which comprises blending from 0.1 to 3% by mass of4-tert-butyl-4′-methoxydibenzoyl-methane.

[0030] [21] An ultraviolet-protecting cosmetic material comprising thecosmetic composition described in any one of [1] to [17] above.

[0031] [22] The ultraviolet-protecting cosmetic material as described in[21] above, which is a W/O or O/W milky lotion, a cream, a foundation ora jell.

[0032] In the present invention, “silica-, alumina- oralumina/silica-coated particulate titanium oxide and silica-, alumina-or alumina/silica-coated particulate zinc oxide” include the following:

[0033] (i) Particulate titanium oxide coated with silica and particulatezinc oxide coated with silica.

[0034] (ii) Particulate titanium oxide coated with silica andparticulate zinc oxide coated with alumina.

[0035] (iii) Particulate titanium oxide coated with silica andparticulate zinc oxide coated with a mixture of alumina and silica.

[0036] (iv) Particulate titanium oxide coated with alumina andparticulate zinc oxide coated with silica.

[0037] (v) Particulate titanium oxide coated with alumina andparticulate zinc oxide coated with alumina.

[0038] (vi) Particulate titanium oxide coated with alumina andparticulate zinc oxide coated with a mixture of alumina and silica.

[0039] (vii) Particulate titanium oxide coated with a mixture of aluminaand silica and particulate zinc oxide coated with silica.

[0040] (viii) Particulate titanium oxide coated with a mixture ofalumina and silica and particulate zinc oxide coated with alumina.

[0041] (ix) Particulate titanium oxide coated with a mixture of aluminaand silica and particulate zinc oxide coated with a mixture of aluminaand silica.

BRIEF DESCRIPTION OF DRAWINGS

[0042]FIG. 1 is a scatter diagram showing light transmittance ofsilica-coated titanium oxide and silica-coated zinc oxide determined bya Cosmol method (concentration: 1% by mass, cell: 0.1 mm).

BEST MODE FOR CARRYING OUT THE INVENTION

[0043] The mode for carrying out the invention is described in detailbelow, however, the present invention is not limited thereto.

[0044] SPF is an abbreviation of Sun Protection Factor and this is avalue measured under test conditions according to the standards of SPFmeasuring method (JCIA method) provided on January, 1992 by JapanCosmetic Industry Association (JCIA). This value (sun protection factor)indicates an effect of preventing sunburn (i.e., erythema primarilyresultant from sunburn by UVB).

[0045] The SPF is determined by the following formula (I):$\begin{matrix}{{SPF} = \frac{{{minimum}\quad {erythema}\quad {dose}\quad ({MED})\quad {of}\quad {skin}\quad {applied}\quad {with}\quad {sunscreen}}\quad}{{{minimum}\quad {erythema}\quad {dose}\quad ({MED})\quad {of}\quad {unapplied}\quad {skin}}\quad}} & (I)\end{matrix}$

[0046] Theoretically, a sunscreen having an SPF of 30 is known to have asufficiently high effect of UVB ultraviolet protection and even when anaverage type of person applied with the sunscreen to an amount (2mg/cm²) prescribed by the JCIA method basks in the sun all day, sunburndoes not occur. However, the SPF is preferably 40 or more.

[0047] PA is an abbreviation of Protection Grade of UVA and this is avalue measured under test conditions according to the standards of UVAprotection effect measuring method provided on January, 1996 by JapanCosmetic Industry Association. This value (UVA protection factor)indicates a persistent pigment darkening (primarily caused by UVA)protection. It is defined that PFA of 2 to less than 4 is “PA+”, PFA of4 to less than 8 is “PA++”, and PFA of 8 or more is “PA+++”.

[0048] PFA is determined by the following formula (II): $\begin{matrix}{{PFA} = \frac{{Minimum}\quad {persistent}\quad {pigment}\quad {darkening}\quad {dose}\quad ({MPPD})\quad {of}\quad {skin}\quad {applied}\quad {with}\quad {sunscreen}}{{minimum}\quad {persistent}\quad {pigment}\quad {darkening}\quad {dose}\quad ({MPPD})\quad {of}\quad {unapplied}\quad {skin}}} & ({II})\end{matrix}$

[0049] Theoretically, a sunscreen having a PFA of “PA++” is known tohave a sufficiently high effect of UVA ultraviolet protection and evenwhen an average type of person applied with the sunscreen to an amount(2 mg/cm²) prescribed by JCIA basks in the sun all day, persistentpigment darkening does not occur. However, the PFA is preferably PA+++or more.

[0050] The W value is a whiteness degree measured using the XYZ colorspecification system provided by the CIE (International Commission onIllumination). In the present invention, the W value used is calculatedby the following formula (III):

W=0.847Z   (III)

[0051] As the W value is larger, the whiteness is higher, that is, whena sunscreen is applied to skin, the unpleasant whiteness is moreserious.

[0052] In the present invention, particulate titanium oxide andparticulate zinc oxide are used at a specific mass ratio, whereby theobtained ultraviolet-protecting cosmetic composition can maintain thesame capability of ultraviolet protection as in the sole use ofparticulate titanium oxide, can have a W value of 20 or less and hightransparency and can ensure good feeling on use and high stability.

[0053] According to the present invention, the mass ratio of particulatetitanium oxide to particulate zinc oxide is 1:4 to 2:3, preferably 1:3to 2:3.

[0054] If the amount of titanium oxide as expressed by the mass ratio ofparticulate titanium oxide to particulate zinc oxide exceeds 2:3,unpleasant whiteness is intensified due to titanium oxide, whereas ifthe amount of titanium oxide as expressed by the mass ratio ofparticulate titanium oxide to particulate zinc oxide is less than 1:4,the ultraviolet protection may disadvantageously decrease despite goodtransparency at the time of application.

[0055] In the present invention, the term “maintain the same capabilityof ultraviolet protection” means a range including a variation of about5%, for example, a range from 40 to 44 for the SPF value of 42 and arange from 7.5 to 8.5 for the PFA value of 8.

[0056] In the present invention, when the cosmetic composition of thepresent invention is applied to a thickness of 10 μm, the whitenessdegree W value measured using the CIE color specification system is 20or less, preferably 15 or less. If the W value exceeds 20, this meansthat when the cosmetic composition is actually applied to skin,unpleasant whitening is generated, for example, with an applied amountprescribed in the JCIA method (2 mg/cm²).

[0057] The coated particulate titanium oxide and coated particulate zincoxide, which are coated with silica, alumina or silica/alumina, aredescribed below. In the present invention, silica coating is preferred.

[0058] The cosmetic composition of the present invention can usesilica-coated particulate titanium oxide and silica-coated particulatezinc oxide which are obtained by a method of bringing particulatetitanium oxide and particulate zinc oxide (at a mass ratio of 1:4 to2:3) each having an average primary particle size of 0.01 to 0.2 μm intocontact with a silica film-forming composition comprising water, analkali, an organic solvent and a silicic acid having neither an organicgroup nor a halogen or a precursor capable of producing the silicicacid, with the water/organic solvent ratio by volume being from 0.1 to10 and the silicon concentration being 0.0001 to 5 mol/liter, toselectively coat the surface of particulate titanium oxide orparticulate zinc oxide with dense silica.

[0059] In this case, after the particulate titanium oxide and theparticulate zinc oxide powder at a ratio described above are eachindependently contacted with the silica film-forming composition toperform the coating with silica, the obtained silica-coated particulatetitanium oxide and the silica-coated particulate zinc oxide may beblended at a mass ratio of 1:4 to 2:3.

[0060] The silica-coated titanium oxide or silica-coated zinc oxidewhich can be more suitably used in the cosmetic composition of thepresent invention is coated with a dense silica film such that the ratioI of the absorption peak intensity at 1,150 to 1,250 cm⁻¹ to theabsorption peak intensity at 1,000 to 1,100 cm⁻¹ on the infraredabsorption spectrum (I=I₁/I₂, wherein I₁ is an absorption peak intensityat 1,150 to 1,250 cm⁻¹ and I₂ is an absorption peak intensity at 1,000to 1,100 cm⁻¹) is 0.2 or more and the refractive index is 1.435 or more.

[0061] In the present invention, the silicic acid for use in the silicafilm-forming composition is an orthosilicic acid or a polymer thereof,such as metasilicic acid, mesosilicic acid, mesotrisilicic acid andmesotetrasilicic acid, described, for example, in the paragraph “SilicicAcid” of Encyclopaedia Chimica, 7th imp., Kyoritsu Shuppan (Mar. 15,1969). The silicic acid does not contain an organic group or a halogen.

[0062] The composition containing a silicic acid can be obtained byadding water, an alkali and an organic solvent, for example, totetraalkoxysilane (Si(OR)₄, wherein R is a hydrocarbon group, preferablyan aliphatic group of C₁ to C₆), specifically a precursor such astetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane,tetraisopropoxy silane and tetra-n-butoxy silane, stirring the mixtureand thereby allowing a hydrolysis reaction to proceed.

[0063] This method is practical and preferred because of easiness inhandling or operation. Among those materials, tetraethoxysilane ispreferred.

[0064] A compound having a hydrophobic group such as hydrocarbon group,a halogen or a hydrogen, represented by the formula X_(n)Si(OH)_(4−n)(wherein X is a hydrocarbon group, a halogen or a hydrogen and n is aninteger of 1, 2 or 3) is different from the silicic acid for use in thepresent invention, accordingly, trialkoxyalkylsilane,dialkoxy-alkyldialkylsilane, trialkoxysilane, dialkoxysilane and thelike are not suitable as the precursor.

[0065] The composition containing a silicic acid can also be obtained bya method of hydrolyzing silane tetrahalogenide while adding theretowater, an alkali and an organic solvent, a method of adding an alkaliand an organic solvent to water glass, or a method of treating waterglass with a cationic exchange resin and adding thereto an alkali and anorganic solvent. Tetraalkoxysilane, silane tetrahalogenide and waterglass used as the starting material of silicic acid are not particularlylimited and those widely and commonly used in industry or as a reagentmay be used, however, a higher purity material is suitable. The silicafilm-forming composition for use in the present invention may contain anunreacted product of the above-described starting material for silicicacid.

[0066] The amount of silicic acid is not particularly limited but ispreferably from 0.0001 to 5.0 mol/liter, more preferably from 0.001 to 5mol/liter, in terms of the silicon concentration. If the siliconconcentration is less than 0.0001 mol/liter, the silica film is formedat a very low rate and this is not practical, whereas if the siliconconcentration exceeds 5 mol/liter, silica particles may be produced inthe composition without forming a coating and this is not preferred.

[0067] The silicon concentration may be calculated from the amount of,for example, tetraalkoxysilane added but can also be measured by theatomic absorption spectrochemical analysis of the composition. Themeasurement may be performed using a spectrum of silicon at a wavelengthof 251.6 nm for the analytical line and acetylene/nitrous oxide for theframe.

[0068] The water used for the silica film-forming composition is notparticularly limited but water from which particles are removed byfiltration or the like is preferably used, because if the water containsparticles, the particles may be disadvantageously mixed into the productas an impurity.

[0069] The water for use in the silica film-forming composition ispreferably used in an amount of giving a water/organic solvent ratio of0.1 to 10 in terms of the volume ratio. If the water/organic solventratio by volume departs from this range, the film formation may fail orthe film formation rate may extremely decreases. The water/organicsolvent ratio by volume is more preferably from 0.1 to 0.5. Insofar asthe water/organic solvent ratio by volume is from 0.1 to 0.5, the kindof alkali used is not limited. In the case where the water/organicsolvent ratio by volume is 0.5 or more, the coating is preferably formedusing an alkali metal-free alkali such as ammonia, ammoniumhydrogencarbonate and ammonium carbonate.

[0070] Examples of the alkali used for the silica film-formingcomposition include inorganic alkalis such as ammonia, sodium hydroxideand potassium hydroxide; inorganic alkali salts such as ammoniumcarbonate, ammonium hydrogencarbonate, sodium carbonate and sodiumhydrogencarbonate; organic alkalis such as monomethylamine,dimethylamine, trimethylamine, monoethylamine, diethylamine,triethylamine, pyridine, aniline, choline, tetramethylammonium hydroxideand guanidine; and alkali salts of organic acid, such as ammoniumformate, ammonium acetate, monomethylamine formate, dimethylamineacetate, pyridine lactate guanidinoacetic acid and aniline acetate,however, the present invention is not limited thereto.

[0071] Among these, in view of the control of reaction rate, ammonia,ammonium carbonate, ammonium hydrogen carbonate, ammonium formate,ammonium acetate, sodium carbonate and sodium hydrogencarbonate arepreferred. In the silica film-forming composition, the above-describedalkalis may be used individually or in combination of two or morethereof.

[0072] The purity of alkali for use in the present invention is notparticularly limited and an alkali widely and commonly used in industryor as a reagent may be used, but a higher purity alkali is preferred.

[0073] The effective means for increasing the silica film-forming rateis to elevate the temperature at the time of film formation. In thiscase, the alkali and the organic solvent used are preferably selectedfrom those which are not easily volatilize or decompose at the filmformation temperature.

[0074] In the present invention, even when the alkali for film formationis added in a trace amount, for example, in the case of sodiumcarbonate, on the order of 0.002 mol/liter, the film formation may beattained but the alkali may also be added in a large amount on the orderof 1 mol/liter. However, if a solid alkali is added in excess ofsolubility, the alkali is mixed into the metal oxide powder as animpurity and this is not preferred.

[0075] By using an alkali not containing an alkali metal as a maincomponent, the prepared particulate silica-coated metal oxide can bereduced in the alkali metal content. Among such alkalis, ammonia,ammonium carbonate and ammonium hydrogencarbonate are preferred in viewof film formation rate, easiness in the removal of residual matter andthe like.

[0076] In the present invention, the organic solvent used for the silicafilm-forming composition is preferably an organic solvent which canprovide the composition as a uniform solution. Examples thereof includealcohols such as methanol, ethanol, propanol and pentanol; ether-acetalssuch as tetrahydrofuran and 1,4-dioxane; aldehydes such as acetaldehyde;ketones such as acetone, diacetone alcohol and methyl ethyl ketone; andpolyhydric alcohol derivatives such as ethylene glycol, propylene glycoland diethylene glycol. Among these, in view of the control of reactionrate, alcohols are preferred and ethanol is more preferred. Theseorganic solvents may be used individually or in combination of two ormore thereof.

[0077] The purity of the organic solvent for use in the silicafilm-forming composition is not particularly limited and an organicsolvent widely and commonly used in industry or as a reagent may beused, but a higher purity organic solvent is preferred.

[0078] In preparing the silica film-forming composition, a generalmethod for preparing a solution may be used. For example, a method ofadding an alkali and water each in a predetermined amount to an organicsolvent, followed by stirring, and then adding tetraethoxysilane,followed by stirring, may be used. In this mixing, whichever addedearlier, a coating can be formed. In mixing water and tetraethoxysilane,both are preferably diluted with an organic solvent in view of thecontrol of reaction.

[0079] The thus-prepared silica film-forming composition is a stablecomposition and causes substantially no deposition or precipitationbefore the composition is brought into contact with metal oxideparticles. When the metal oxide particles are contacted with thecomposition, silica starts to selectively deposit on the surface of themetal oxide particle.

[0080] The production method of titanium oxide as a starting material ofthe silica-coated titanium oxide is not particularly limited and anymethod may be used. The titanium oxide which can be used may be producedby any production method such as high-temperature vapor phase oxidationof TiCl₄, vapor phase hydrolysis of TiCl₄, sulfuric acid process andchlorine process. With respect to the crystal form of titanium oxide,any of amorphous, rutile, anatase, brookite and the like may be used anda mixture thereof may also be used. However, the titanium oxide ispreferably reduced in impurities as much as possible and furthermore, inview of the control of secondary particle size, is preferably reduced inthe aggregation.

[0081] The production method of zinc oxide as a starting material of thesilica-coated zinc oxide is not particularly limited and any method maybe used. The zinc oxide which can be used may be a zinc oxide producedby evaporation-oxidizing electrolytic zinc metal, a zinc hydroxideobtained by neutralizing an aqueous solution of water-soluble salt suchas zinc sulfate or zinc chloride, or a zinc oxide obtained by calciningzinc hydroxide, zinc carbonate, zinc sulfide, zinc oxalate or the like.A mixture thereof may also be used. However, the zinc oxide ispreferably reduced in impurities as much as possible and furthermore, inview of the control of secondary particle size, is preferably reduced inthe aggregation.

[0082] In the present invention, titanium oxide and zinc oxide areimmersed in the silica film-forming composition and kept at apredetermined temperature, whereby silica is allowed to deposit on thesurfaces of titanium oxide and zinc oxide to form a silica film. Withrespect to the method for forming a silica film, a method of previouslypreparing the film-forming composition and charging titanium oxide andzinc oxide in the composition to form a silica film, a method ofpreviously suspending titanium oxide and zinc oxide in a solvent, addingother raw material components to prepare a film-forming composition andthereby forming a silica film, or the like may be used. In other words,the order of charging raw materials of the film-forming composition, thetitanium oxide and the zinc oxide is not particularly limited andwhichever charged earlier, a silica film can be formed.

[0083] Among these methods, a method of preparing a suspensioncontaining titanium oxide, zinc oxide, water, an organic solvent and analkali and adding thereto dropwise tetraalkoxysilane diluted with anorganic solvent at a constant rate is preferred, because a more densesilica film can be formed and a continuous process useful in industrycan be established.

[0084] The silica film grows by the selective deposition on the surfaceof metal oxide and therefore, as the film formation time is longer, thecoating can have a larger thickness. Of course, when the majority ofsilicic acid in the film-forming composition is consumed by theformation of coating, the film formation rate decreases, however, bysequentially adding silicic acid in an amount corresponding to theconsumed portion, the silica film can be continuously formed at apractical film formation rate. In particular, when the silica film isformed by holding titanium oxide and zinc oxide in the film-formingcomposition having added thereto a silicic acid corresponding to thedesired thickness of silica film for a predetermined time, therebyconsuming the silicic acid, and a silicic acid corresponding to theconsumed portion is further added after the silica-coated titanium oxideand silica-coated zinc oxide are taken out from the system, thecomposition can be continuously used in the film formation on nexttitanium oxide and zinc oxide and a continuous process having highprofitability and good productivity can be established.

[0085] For example, in the case of a method of preparing a suspensioncontaining titanium oxide, zinc oxide, water, an organic solvent and analkali and adding thereto dropwise tetraalkoxysilane diluted with anorganic solvent at a constant rate, a solution obtained by dilutingtetra-alkoxysilane corresponding to the desired thickness of silica filmwith an organic solvent is added dropwise at a constant rate agreeingwith the hydrolysis rate, whereby the tetraalkoxysilane is completelyconsumed, a dense silica film having a desired thickness can be formedand when the produced silica-coated titanium oxide and silica-coatedzinc oxide are taken out from the system, a high-purity product free ofresidual unreacted tetraalkoxysilane can be obtained. Of course, thesolvent after the silica-coated titanium oxide and the silica-coatedzinc oxide are taken out can be recycled in the next film formation anda process with high profitability and high productivity can beestablished.

[0086] The temperature at the formation of silica film is notparticularly limited but is preferably from 10 to 100° C., morepreferably from 20 to 50° C. As the temperature is higher, the filmformation rate is more increased, however, if the temperature isexcessively high, the solution composition cannot be maintained constantdue to volatilization of components in the composition, whereas if thetemperature is too low, the film formation proceeds at a low rate andthis is not practical.

[0087] The pH at the film formation may be sufficient if it is in thealkali region, in view of denseness of film. However, in the case offorming silica film on a metal oxide having a solubility which increasesdepending on the pH, the pH of the film-forming composition ispreferably controlled by adjusting the amount of alkali added. In thiscase, with the change in the amount of alkali added, the hydrolysis rateof, for example, tetraalkoxysilane changes and therefore, the filmformation temperature or the water content in the film-formingcomposition must be adjusted to give an appropriate hydrolysis rate.

[0088] After the film formation, the silica-coated titanium oxide orsilica-coated zinc oxide can be isolated by solid-liquid separation. Theisolation may be performed by a general separation method such asfiltration, centrifugal sedimentation and centrifugal separation.

[0089] By performing drying after the solid-liquid separation, theobtained silica-coated titanium oxide and silica-coated zinc oxide canbe reduced in the water content. In the drying, a general drying methodmay be used, such as natural drying, hot air drying, vacuum drying andspray drying. In the case where aggregation of particles occurs by thedrying, the aggregate may be ground.

[0090] The silica film of the silica-coated titanium oxide andsilica-coated zinc oxide according to the present invention has a veryhigh shape-following capability and since primary particles of titaniumoxide and zinc oxide as a substrate all are coated with a dense silicafilm having high covering power, the silica film is not broken by thegrinding. Accordingly, the grinding method is not particularly limitedand a jet mill, a high-speed rotary mill or other grinder may be used.

[0091] In the silica-coated titanium oxide and zinc oxide particlesobtained by the above-described method, the ratio I of the absorptionpeak intensity at 1,150 to 1,250 cm⁻¹ to the absorption peak intensityat 1,000 to 1,100 cm⁻¹ on the infrared absorption spectrum (I=I₁/I₂,wherein I₁ is an absorption peak intensity at 1,150 to 1,250 cm⁻¹ and I₂is an absorption peak intensity at 1,000 to 1,100 cm⁻¹) is 0.2 or moreand the refractive index is 1.435 or more. In other words, the silicacoating has the same chemical bond or functional group as in a silicafilm obtained by a conventional sol-gel method without performingcalcination and therefore, exhibits specific physical propertiesdifferent in the hydrophilicity, lipophilicity or the like from a silicacoating obtained through calcination, nevertheless, this silica coatingis dense and practical.

[0092] The term “dense” as used in the present invention means that thesilica film formed has a high density and is uniform and free ofpinholes or cracks. The term “practical” as used herein means that thebonding between silica and the substrate titanium oxide or zinc oxide(—Si—O-M- bonding, wherein M is Ti or Zn) is strong enough not to causestripping or the like of the coating and the physical properties ofsilica-coated titanium oxide and silica-coated zinc oxide are notreadily changed.

[0093] Furthermore, this silica film has good conformability to acomplicated shape of the substrate titanium oxide or zinc oxide and evenif the thickness is as small as about 0.5 nm, the film exhibits goodcovering power and high capability of concealing the photocatalyticactivity. Furthermore, since the silica film can be very reduced in thealkali metal content, the silica film is not dissolved even in anatmosphere of high temperature and high humidity and the silica-coatedtitanium oxide and zinc oxide particles can be prevented from changingin the physical properties.

[0094] The silica-coated titanium oxide and the silica-coated zinc oxidefor use in the cosmetic composition of the present invention each has asilica film thickness of 0.1 to 100 nm, preferably from 0.3 to 50 nm,more preferably from 0.5 to 25 nm. If the thickness of silica film isless than 0.1 nm, a sufficiently high effect of concealing thephotocatalytic activity cannot be obtained and the obtained cosmeticcomposition may disadvantageously fail in having preparation formstability, whereas if it exceeds 100 nm, the obtained cosmeticcomposition may not have sufficiently high ultraviolet-shielding abilityand this is not preferred.

[0095] The silica-coated titanium oxide and the silica-coated zinc oxidefor use in the present invention each has a primary particle size of0.01 to 0.2 μm, preferably from 0.01 to 0.12 μm. If the primary particlesize departs from this range, the obtained cosmetic composition may failin providing a high ultraviolet-shielding effect and this is notpreferred.

[0096] The term “primary particle” as used in the present inventionindicates a particle defined in Kiichiro Kubo et al., Funtai (Powder),pp. 56-66 (1979).

[0097] In the present invention, the silica-coated titanium oxide andthe silica-coated zinc oxide each has a photocatalytic activity,measured by a tetralin auto-oxidation method, of 60 Pa/min or less,preferably 50 Pa/min or less. If the photocatalytic activity measured bythe tetralin auto-oxidation method exceeds 60 Pa/min, the effect ofsuppressing the photocatalytic activity may not be successfully attainedand the obtained cosmetic composition may disadvantageously fail inhaving high safety and high stability.

[0098] The silica-coated titanium oxide and the silica-coated zinc oxidefor use in the present invention each preferably has a dye discolorationrate, measured by a Sunset Yellow method, of 0.1 or less, morepreferably 0.05 or less. If the dye discoloration rate exceeds 0.1, theeffect of suppressing the photocatalytic activity is not sufficientlyhigh and the obtained cosmetic composition may fail in having highsafety and high stability.

[0099] The silica-coated titanium oxide and the silica-coated zinc oxidefor use in the present invention each preferably has an organicultraviolet absorber decomposition rate, measured by a Parsol method, of0.02 or less, more preferably 0.01 or less. If the organic ultravioletabsorber decomposition rate measured by the Parsol method exceeds 0.02,the effect of suppressing the photocatalytic activity is notsufficiently high and the obtained cosmetic composition maydisadvantageously fail in having high safety and high stability.

[0100] The silica-coated titanium oxide and the silica-coated zinc oxidefor use in the present invention each preferably has an organicultraviolet absorber decomposition percentage, measured by an ethylhexylp-methoxycinnamate method, of 5% or less, more preferably 3% or less. Ifthe organic ultraviolet absorber decomposition percentage measured bythe ethylhexyl p-methoxycinnamate method exceeds 5%, the effect ofsuppressing the photocatalytic activity is not sufficiently high and theobtained cosmetic composition may disadvantageously fail in having highsafety and high stability.

[0101] In the present invention, the silica-coated titanium oxide andthe silica-coated zinc oxide need not be particularly calcined but, ifdesired, may be calcined before use.

[0102] In the present invention, the silica-coated titanium oxide andthe silica-coated zinc oxide each may be subjected to a treatment ofrendering the surface hydrophobic. Particularly, in the case where thesilica-coated titanium oxide and silica-coated zinc oxide are used bydispersing these in an oil at the formulation of a cosmetic material,the treatment for rendering the surface hydrophobic is preferablyperformed before the use. The surface may be rendered hydrophobic bycoating the surface using a hydrophobizing agent which is one or moreselected from the group consisting of silicone oils, alkoxysilanes,silane coupling agents, and higher fatty acid salts.

[0103] Examples of the hydrophobizing agents which can be used includehigher fatty acids such as waxes, higher fatty acid glyceryls, higherfatty acids, polyvalent metal salts of higher fatty acids, andpolyvalent metal salts of sulfated higher aliphatic compounds; higheralcohols and derivatives thereof; fluoroorganic compounds such asperfluorinated or partially fluorinated higher fatty acids and higheralcohols; and organosilicon compounds such as silicone oils (such asdimethylpolysiloxane, methylhydrogenpolysiloxane, and modified siliconeoils), silane coupling agents, alkoxysilanes, chlorosilanes, andsilazanes. Polyvalent metal salts of higher fatty acids, silicone oils,silane coupling agents, and alkoxysilanes are preferably used. Inparticular, alkoxysilanes and silane coupling agents are preferably usedin view of their effects obtained when they are actually used. Thesurface treatment with an alkoxysilane may be carried out using a liquidphase process or a dry process. However, a liquid phase process is morepreferably employed for the following reasons: a liquid phase processmakes it possible to continuously surface-treat a silica-coated metaloxide with a hydrophobizing agent by carrying out silica coating bybringing metal oxide particles into contact with a silica film-formingcomposition, and then, without separating the particles out, by adding ahydrophobizing agent and adding, if necessary, an alkali, water, and anorganic solvent; therefore, a liquid phase process is an industriallyadvantageous process because intermediate steps of separating andrefining the particles can be omitted.

[0104] The amount of the hydrophobizing agent to be coated may be anyamount greater than or equal to the minimum coating amount sufficient tocompletely cover the surfaces of the silica-coated metal oxideparticles, which are the raw material. The upper limit of the amount ofthe hydrophobizing agent used is generally not determined. However, anexcessive amount is uneconomical since the amount of hydrophobizingagent precipitating in areas other than the surfaces of the metal oxideparticles increases. The amount of the hydrophobizing agent to be coatedis from 0.5 to 30% by mass, preferably from 0.5 to 20% by mass, morepreferably from 0.8 to 10% by mass, based normally on the amount of thesilica-coated metal oxide particles. If the amount of the hydrophobizingagent to coat is less than 0.5% by mass, low hydrophobicity results,whereas if it exceeds 30% by mass, the capability of ultravioletprotection may decrease in some cases.

[0105] The cosmetic composition of the present invention, which containsthe above-described silica-coated titanium oxide and silica-coated zincoxide, can be produced by a normal production method using generalstarting materials which can be blended in a cosmetic composition, tohave an arbitrary preparation form such as W/O or O/W emulsion, liquid,solid and jell.

[0106] The cosmetic composition of the present invention is composed ofa powder portion and an oil portion. The material constituting thepowder portion includes, in addition to the silica-coated titanium oxideand silica-coated zinc oxide, an extender pigment (e.g., mica, talc,kaolin, calcium carbonate, magnesium carbonate, silicic acid anhydride,aluminum oxide, barium sulfate), a white pigment (e.g., titaniumdioxide, zinc oxide) and a color pigment (e.g., red oxide of iron,yellow oxide of iron, black oxide of iron, chromium oxide, ultramarine,iron blue, carbon black) . These materials may be appropriately blended.In order to further improve the feeling on use, a spherical powder(e.g., nylon powder, polymethyl methacrylate powder) may also be used.

[0107] Furthermore, similarly to the silica-coated titanium oxide andsilica-coated zinc oxide, fine particulate cerium oxide and the like maybe used for protecting ultraviolet rays, and this particle is alsopreferably coated with the dense silica film of the present invention.

[0108] The oil portion blended in the cosmetic composition of thepresent invention includes liquid petrolatum, squalane, castor oil,glyceryl diisostearate, glyceryl triisostearate, glyceryltri-2-ethylhexanoate, isopropyl myristate, glyceryl triisostearate,dimethylpolysiloxane, methylphenyl poly-siloxane, petrolatum,diisostearyl maleate, purified lanolin and the like, however, thepresent invention is not limited thereto.

[0109] In the oil portion, an organic ultraviolet absorber may also beblended. The organic ultraviolet absorber means an organic compoundhaving a function of absorbing an ultraviolet ray, consuming the energyfor the generation of heat, oscillation, fluorescence, radical or thelike, and thereby protecting skin.

[0110] The ultraviolet absorber which can be used in the cosmeticcomposition of the present invention is not particularly limited butexamples thereof include ultraviolet absorbers of benzophenone type,salicylic acid type, PABA type, cinnamic acid type, dibenzoylmethanetype and urocanic acid type. Specific examples thereof include2-hydroxy-4-methoxybenzophenone,2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, sodium2-hydroxy-4-methoxybenzophenone-5-sulfonate,dihydroxydimethoxybenzophenone, sodiumdihydroxydiimethoxybeiizophenone-sulfonate, tetrahydroxybenzophenone,p-aminobenzoic acid, ethyl p-aminobenzoate, glyceryl p-aminobenzoate,amyl p-dimethylaminobenzoate, octyl p-dimethylaminobenzoate, ethylp-methozycinnamate, isopropyl p-methoxycinnamate, octylp-methoxycinnamate, 2-ethylhexyl p-methoxycinnamate, sodiump-methoxycinnamate, glyceryl di-p-methoxycinnamatemono-2-ethylhexanoate, octyl salicylate, phenyl salicylate, homomenthylsalicylate, dipropyleneglycol salicylate, ethyleneglycol salicylate,myristyl salicylate, methyl salicylate, urocanic acid, ethyl urocanate,4-t-butyl-4′-methoxydibenizoylmethane,2-(2′-hydroxy-5′-methylphenyl)benzotriazole, and methyl anthranylate.

[0111] Among these, in view of ultraviolet protection and skinirritation, 2-ethylhexyl p-methoxycinnamate and4-tert-butyl-4′-methoxydibenzoylmethane are preferred,- and 2-ethylhexylp-methoxycinnamate is more preferable.

[0112] The amount of the ultraviolet absorber blended is from 0.1 to 10%by mass based on the entire amount of the cosmetic composition, however,an appropriate amount is preferably determined according to theultraviolet ray-absorbing power of the absorber. In the presentinvention, in view of ultraviolet protection, 2-ethylhexylp-methoxycinnamate is blended in an amount of 2 to 8% by mass,preferably from 2 to 7% by mass, more preferably from 3 to 6% by mass,and 4-tert-butyl-4′-methoxydibenzoylmethane is blended in an amount of0.1 to 3% by mass, preferably from 0.3 to 3% by mass, more preferablyfrom 0.5 to 2% by mass.

[0113] The silica-coated titanium oxide and silica-coated zinc oxideused in the present invention each provides a high effect of suppressingthe photocatalytic activity and therefore, even when these metal oxidesare used in combination with the organic ultraviolet absorber, theabsorber can be prevented from decomposing, so that the obtainedcosmetic composition can have high ultraviolet-shielding effect andmoreover, can maintain the effect for a long period of time.

[0114] The cosmetic composition of the present invention may furthercontain an existing emulsifier in a general concentration. Examples ofthe emulsifier include those described in Japanese Standards of CosmeticIngredients (JSCI), 2nd Edition, Annotation, compiled by Nippon KoteishoKyokai, issued by Yakuji Nippo, Ltd. (1984), Specifications ofIngredient Other Than Those Listed in JSCI, supervised by ExaminationDivision, Pharmaceutical Affairs Bureau, Ministry of Health and Welfare,issued by Yakuji Nippo, Ltd. (1993), Specifications of Ingredient OtherThan Those Listed in JSCI, Supplement, supervised by ExaminationDivision, Pharmaceutical Affairs Bureau, Ministry of Health and Welfare,issued by Yakuji Nippo, Ltd. (1993), The Comprehensive LicensingStandards of Cosmetics by Category, supervised by Examination Division,Pharmaceutical Affairs Bureau, Ministry of Health and Welfare, issued byYakuji Nippo, Ltd. (1993), and Kesho-hin Genryo Jiten (Handbook ofCosmetic Ingredients), Nikko Chemicals (1991). All emulsifies describedin these publications can be used. In addition, tocopheryl phosphatesmay also be used as the emulsifier.

[0115] In the cosmetic composition of the present invention, an existingantiinflammatory or antiphlogistic ingredient may be used in combinationor may be mixed, so as to help the protection against inflammation byultraviolet rays. The antiphlogistic ingredient which can be added tothe cosmetic composition of the present invention is not particularlylimited but examples thereof include aniline derivative-typeantiphlogistic, salicylic acid derivative-type antiphlogistic,pyrazolone derivative-type antiphlogistic, indomethacin-typeantiphlogistic, mefenamic acid-type antiphlogistic and antiinflammatoryenzymatic agent, however, the present invention is not limited thereto.

[0116] When an antioxidant as a substance having an oxidation-inhibitingactivity is used in combination in the cosmetic composition of thepresent invention, the amount of free radicals generated by ultravioletrays can be reduced and thereby the silica-coated titanium oxide and thesilica-coated zinc oxide can be more suppressed in their photocatalyticactivity, as a result, a safe cosmetic composition having a remarkablyexcellent preparation form stability and a low phototoxicity can beobtained.

[0117] The antioxidant having an effect of suppressing thephotocatalytic activity, which can be used in the cosmetic compositionof the present invention, is not particularly limited but examplesthereof include vitamin A, β-carotene, astaxanthin, vitamin B, vitaminC, magnesium L-ascorbic acid-2-phosphate, sodium L-ascorbicacid-2-phosphate, magnesium sodium L-ascorbic acid-2-phosphate,L-ascorbic acid-2-glucoside, L-ascorbic acid-2-phosphoricacid-5,6-benzylidene, natural vitamin E, dl-α-tocopherol,dl-α-tocopheryl acetate, sodium dl-α-tocopheryl phosphate, ubiquinone,derivatives of these vitamins, cysteine, glutathione, glutathioneperoxidase, SOD, catalase, citric acid, phosphoric acid, polyphenol,catechine, tea extract, kojic acid, nucleic acid, hydroquinone andarbutin. One or more selected from these antioxidants may be blended.

[0118] Other than the above-described ingredients, the cosmeticcomposition of the present invention may contain ingredients commonlyblended in cosmetic compositions, such as fats and oils, waxes,hydrocarbons, fatty acids, alcohols, polyhydric alcohols, saccharides,esters, metal soaps, water-soluble polymer compounds, surfactants,antioxidants, microbicide•antiseptics, vitamins, hormones and coloringmaterials.

[0119] The silica-coated titanium oxide and the silica-coated zinc oxideare preferably blended together in the cosmetic composition of thepresent invention in total amount of 5 to 25% by mass, more preferablyfrom 5 to 20% by mass, based on the total amount of the cosmeticcomposition. If the amount blended is less than 5% by mass, the effectof protecting ultraviolet rays is not sufficiently high, whereas if thesilica-coated titanium oxide and the silica-coated zinc oxide each isblended in an amount in excess of 25% by mass, the feeling on use isdisadvantageously poor because unpleasant whitening occurs at the timeof application to skin or the skin is roughened.

[0120] The titanium oxide used for the purpose of protecting ultravioletrays is generally higher in the proportion of rutile form than that ofanatase form. However, the silica-coated titanium oxide for use in thepresent invention is greatly reduced in free radicals generated byultraviolet rays and therefore, is not bound to the crystal form.According to the present invention, a safe cosmetic composition havingexcellent preparation form stability and low phototoxicity can beobtained.

[0121] The cosmetic composition of the present invention not only haspreparation form stability and ultraviolet-shielding ability but alsoeven when the particulate titanium oxide and the particulate zinc oxideeach is blended in a high concentration, ensures excellent feeling onuse without causing any creaky feeling or poor extension. The cosmeticcomposition of the present invention also has high transparency and doesnot cause pale finish on makeup as encountered in the case of containinga conventional particulate titanium oxide or particulate zinc oxide.Furthermore, the photocatalytic activity of titanium oxide and zincoxide is sufficiently concealed and therefore, extremely high storagestability can be obtained without accelerating denaturation of otheringredients in the composition.

[0122] The cosmetic composition of the present invention may furthercontain an organic ultraviolet absorber, whereby higherultraviolet-shielding effect and higher preparation form stability canbe achieved. Furthermore, by containing an antioxidant having anoxidation-inhibiting activity, generation of active oxygen and the likecan be greatly reduced and therefore, the cosmetic composition of thepresent invention ensures high safety to human body.

[0123] In the present invention, the thickness and the refractive indexof silica film can be measured by using a silica film formed on asilicon wafer immersed in a system undergoing the synthesis ofsilica-coated titanium oxide and silica-coated zinc oxide. On thissilicon wafer, the same silica film as on the particulate metal oxide isformed. The refractive index of silica film can be determined by anellipsometer (LASSER ELLIPSOMETER ESM-1A, manufactured by ULVAC). Thethickness can be determined using a step gauge.

[0124] The transmission infrared absorption spectrum (FT-IR-8000manufactured by Nippon Bunko K.K.) of silica film of the silica-coatedtitanium oxide or silica-coated zinc oxide can be determined by a KBrmethod. The primary particle size of the silica-coated titanium oxideand the silica-coated zinc oxide and the thickness of silica filmthereof can be determined from an image by a transmission type electronmicroscope.

[0125] The photocatalytic activity, namely, the initial oxygenconsumption rate of the silica-coated titanium oxide and thesilica-coated zinc oxide for use in the present invention can bemeasured by a tetralin auto-oxidation method (see, Manabu Kiyono, SankaTitan—Bussei to Oyo Gijutsu (Titanium Oxide—Physical Properties andApplied Technique), pp. 196-197, Gihodo (1991)). The measurementconditions are such that the temperature is 40° C., tetralin is 20 mland titanium oxide is 0.02 g.

[0126] The photocatalytic activity of the silica-coated titanium oxideand the silica-coated zinc oxide for use in the present invention isfurther determined by a Sunset Yellow method (as a dye discolorationrate), by a Parsol 1789 method or by an ethylhexyl p-methoxycinnamatemethod, which are described in the present specification.

[0127] The light transmittance of the silica-coated titanium oxide andthe silica-coated zinc oxide for use in the present invention isdetermined by a Cosmol method described in the present specification.

[0128] The cosmetic composition of the present invention providesexcellent ultraviolet protection against both UVB and UVA, causesneither unpleasant whitening to the applied skin nor skin irritation andensures good feeling on use and therefore, is suitably used as acosmetic composition having high safety and high stability withoutcausing decomposition of ingredients blended in the cosmetic material,such as organic ultraviolet absorber. The cosmetic composition of thepresent invention is particularly useful as an ultraviolet-protectingcosmetic material such as W/O or O/W milky lotion, cream, foundation andjell.

[0129] Although the above is an explanation of the case where a silicacoated titanium oxide and a silica coated zinc oxide are used, use of atitanium oxide and a zinc oxide in any of the above (ii) to (ix) alsoexert effects similar to the effects of the use of the silica-coatedtitanium oxide and the silica-coated zinc oxide.

EXAMPLES

[0130] The present invention is described in greater detail below byreferring to the Examples.

[0131] However, the present invention is by no means limited to theseExamples.

Production Example 1

[0132] Production 1 of Silica-Coated Titanium Oxide:

[0133] In a 5 L-volume reactor, 400 mL of deionized water, 1,400 mL ofethanol (produced by Junsei Kagaku K.K.) and 75 mL of a 25 mass %aqueous ammonia (produced by Taisei Kako) were mixed and thereinto, 105g of titanium oxide (High-Purity Titanium Oxide F-1, produced by ShowaTitanium Co., Ltd.; primary particle size: 90 nm) was dispersed toprepare Suspension 1. Separately, 193 mL of tetraethoxysilane (producedby Nakarai Tesc), 36 mL of water and 144 mL of ethanol were mixed toprepare Solution 1.

[0134] To Suspension 1 under stirring with a magnetic stirrer, Solution1 was added at a constant rate over 6 hours. The resulting solution wasripened for 12 hours. The film formation and ripening were performed at25° C. Thereafter, the solid contents were separated by centrifugalfiltration, vacuum dried at 50° C. for 12 hours and then hot-air driedat 80° C. for 12 hours to obtain silica-coated titanium oxide.

Production Example 2

[0135] Production 2 of Silica-Coated Titanium Oxide:

[0136] A silica-coated titanium oxide was obtained in the same manner asin Production Example 1 except for using titanium oxide having adifferent primary particle size (High-Purity Titanium Oxide F-4 producedby Showa Titanium Co., Ltd.; primary particle size: 30 nm) in place ofthe titanium oxide of Production Example 1.

Production Example 3

[0137] Production 3 of Silica-Coated Titanium Oxide:

[0138] In a 5 L-volume reactor, 420 mL of deionized water, 1,930 mL ofethanol (produced by Junsei Kagaku K.K.) and 75 mL of a 25 mass %aqueous ammonia (produced by Taisei Kako) were mixed and thereinto, 105g of titanium oxide (High-Purity Titanium Oxide F-4, produced by ShowaTitanium Co., Ltd.; primary particle size: 30 nm) was dispersed toprepare Suspension 2. Separately, 44 mL of tetraethoxysilane (producedby Nakarai Tesc) and 135 mL of ethanol were mixed to prepare Solution 2.

[0139] To Suspension 2 under stirring with a magnetic stirrer, Solution2 was added at a constant rate over 6 hours. The resulting solution wasripened for 12 hours. The film formation and ripening were performed at25° C. Thereafter, the solid-liquid separation and drying were performedin the same manner as in Production Example 1 and the obtained productwas ground in a jet mill to obtain silica-coated titanium oxide.

Production Example 4

[0140] Production 1 of Silica-Coated Zinc Oxide:

[0141] In a 50 L-volume reactor, 18.25 L of deionized water, 22.8 L ofethanol (produced by Junsei Kagaku K.K.) and 124 mL of a 25 mass %aqueous ammonia (produced by Taisei Kako) were mixed and thereinto, 1.74Kg of zinc oxide (High-Purity Zinc Oxide UFZ-40, produced by ShowaTitanium Co., Ltd.; primary particle size: 27 nm) was dispersed toprepare Suspension 3. Separately, 1.62 L of tetraethoxysilane (producedby GE Toshiba Silicone) and 1.26 L of ethanol were mixed to prepareSolution 3.

[0142] To Suspension 3 under stirring, Solution 3 was added at aconstant rate over 9 hours. The resulting solution was ripened for 12hours. The film formation and ripening were performed at 45° C.Thereafter, the solid-liquid separation and drying were performed in thesame manner as in Production Example 1 and the obtained product wasground in a jet mill to obtain silica-coated zinc oxide.

[0143] The silica-coated titanium oxides and silica-coated zinc oxidesobtained in Production Examples 1 to 4 were determined on thetransmission infrared absorption spectrum by a KBr method. As a result,with any particulate metal oxide, an absorption originated from theSi—O—Si stretching vibration was observed at 1,000 to 1,200 cm⁻¹, and anabsorption originated from the C—H stretching vibration was not observedat 2,800 to 3,000 cm⁻¹, whereby the formed film was identified assilica.

[0144] Furthermore, the primary particle size, the thickness of silicafilm, the ratio I between absorption peak intensities on the infraredabsorption spectrum, the refractive index of silica film, and thephotocatalytic activity by a tetralin auto-oxidation method weremeasured. The results obtained are shown together in Table 1 below.TABLE 1 Photo- Primary Film catalytic Particle Thickness, RefractiveActivity, Size, nm nm I Value Index Pa/min Production 90 10  0.5 1.44538 Example 1 Production 30 4 0.5 1.445 49 Example 2 Production 30 1 0.41.440 49 Example 3 Production 27 3 0.45 1.443 39 Example 4

[0145] <Measurement of Light Transmittance, Cosmol Method>

[0146] The silica-coated titanium oxides of Production Examples 2 and 3,the silica-coated zinc oxide of Production Example 4, two kinds ofcommercially available conventional surface-treated titanium oxides(MT500SA produced by Teica Corp. and TTO-S1 produced by Ishihara SangyoKaisha, Ltd.) and a commercially available conventional zinc oxide(ZNO350 produced by Sumitomo Osaka Cement Corp.) were used as testsubstances and measured on the light transmittance by a Cosmol method.More specifically, each test substance was dispersed in polyglyceryltriisostearate (Cosmol 43) to prepare a slurry having a concentration of1%, the slurry was placed in a 0.1 mm-thick quartz cell, and the lighttransmittance was measured by a spectrophotometer (UV-160, manufacturedby Shimadzu Corporation). The results are shown together in FIG. 1.

[0147] It is seen that the silica-coated titanium oxide and thesilica-coated zinc oxide for use in the present invention have highlight-shielding ability in the ultraviolet region and high lighttransmittance in the visible region as compared with the conventionalproducts.

Example 1

[0148] Measurement of Dye Discoloration Rate, Sunset Yellow Method:

[0149] The silica-coated titanium oxides obtained in Production Examples1 to 3, two kinds of respectively corresponding uncoated titaniumoxides, two kinds of commercially available conventional surface-treatedtitanium oxides (MT500SA produced by Teica Corp. and TTO-S1 produced byIshihara Sangyo Kaisha, Ltd.), the silica-coated zinc oxide obtained inProduction Example 4 and an uncoated zinc oxide corresponding theretowere used as test substances and measured on the dye discoloration rateby a Sunset Yellow method.

[0150] First, Sunset Yellow FCF (produced by Wako Pure ChemicalIndustries, Ltd.) as a dye for cosmetics was dissolved in a 98 mass %glycerin to have a dye concentration of 0.02 mass %. Each test substancewas dispersed therein to a concentration of 0.067 mass % and theresulting dispersion solution was irradiated with ultraviolet rays(ultraviolet ray intensity: 1.65 mW/cm²) The absorbance at 490 nm whichis a maximum absorption wavelength of Sunset Yellow FCF was measured toa light pass length of 1 mm by a spectrophotometer (UV-160, manufacturedby Shimadzu Corporation) with the passage of time and the difference(ΔABS₄₉₀/hr) between the absorbance decrease rate here and theabsorbance decrease rate in a null test (no addition of titanium oxideand zinc oxide) was calculated. The results are shown in Table 2. TABLE2 Dye discoloration Rate (ΔABS₄₉₀/hr) Production Example 1 0.05Production Example 2 0.02 Production Example 3 0.10 Production Example 40.00 Conventional Surface-Treated Titanium 0.12 Oxide (MT500SA)Conventional Surface-Treated Titanium 4.19 Oxide (TTO-S1) UncoatedTitanium Oxide (starting 14.30 material of Production Example 1)Uncoated Titanium Oxide (starting 22.88 material of Production Example2) Uncoated Zinc Oxide (starting 8.86 material of Production Example 4)

[0151] The silica-coated titanium oxide and the silica-coated zinc oxidefor use in the present invention had a dye discoloration rate of 0.1(ΔABS₄₉₀/hr) or less in any test substance and this reveals suppressionin the decomposition of dye as compared with uncoated products andconventional surface-treated products.

Example 2

[0152] Measurement of Decomposition Rate of Organic UltravioletAbsorber, Parsol 1789 Method:

[0153] The silica-coated titanium oxides obtained in Production Examples1 to 3, two kinds of respectively corresponding uncoated titaniumoxides, two kinds of conventional surface-treated particulate titanias(MT500SA produced by Teica Corp. and TTO-S1 produced by Ishihara SangyoKaisha, Ltd.), the silica-coated zinc oxide obtained in ProductionExample 4 and an uncoated zinc oxide were used as test substances andmeasured on the organic ultraviolet absorber decomposition rate by aParsol method.

[0154] More specifically, each test substance was dispersed in apolyethylene glycol 300 solution of4-tert-butyl-4′-methoxydibenzoylmethane (Parsol 1789) (0.045% by mass asa Parsol 1789 concentration) to form a 1 wt % slurry. Then, 1.2 g of theslurry was charged in a glass container, ultraviolet rays (1.65 mW/cm²)were irradiated for 10 hours, 1 g was then sampled and thereto, 2 mL ofisopropyl alcohol, 2 mL of hexane and 3 mL of distilled water weresequentially added. The mixture was stirred, Parsol 1789 was extractedin the hexane phase, and the absorbance (at 340 nm) of the hexane phasewas measured to a light pass length of 1 mm by a spectrophotometer(UV-160, manufactured by Shimadzu Corporation). The difference(ΔABS₃₄₀/hr) between the absorbance decrease rate at 340 nm and theabsorbance decrease rate in a null test (no addition of titanium oxideand zinc oxide) was calculated.

[0155] The results obtained are shown together in Table 3. TABLE 3Decomposition Rate (ΔABS₃₄₀/hr) Production Example 1 0.001 ProductionExample 2 0.001 Production Example 3 0.017 Production Example 4 0.002Conventional Surface-Treated 0.024 Titanium Oxide (MT500SA) ConventionalSurface-Treated 0.044 Titanium Oxide (TTO-S1) Uncoated Titanium Oxide(starting 0.120 material of Production Example 1) Uncoated TitaniumOxide (starting 0.175 material of Production Example 2) Uncoated ZincOxide (starting 0.066 material of Production Example 4)

[0156] The silica-coated titanium oxide and silica-coated zinc oxidewhich can be used in the present invention had a decomposition rate of0.02 (ΔABS₃₄₀/hr) or less in any test substance and this reveals thatthe ultraviolet absorber decomposability was extremely low as comparedwith uncoated products and conventional surface-treated products.

Example 3

[0157] Measurement of Decomposition Rate of Organic UltravioletAbsorber, Ethylhexyl p-Methoxycinnamate Method:

[0158] The silica-coated titanium oxides obtained in Production Examples1 to 3, two kinds of respectively corresponding uncoated titaniumoxides, two kinds of conventional surface-treated particulate titanias(MT-100T produced by Teica Corp. and TTO-S1 produced by Ishihara SangyoKaisha, Ltd.), the silica-coated zinc oxide obtained in ProductionExample 4 and an uncoated zinc oxide were used as test substances andmeasured on the organic ultraviolet absorber decomposition percentage byan ethylhexyl p-methoxycinnamate method.

[0159] More specifically, each test substance was dispersed in apolyethylene glycol 300 solution of 2-ethylhexyl p-methoxycinnamate(0.05% by mass as a 2-ethylhexyl p-methoxycinnamate concentration) toform a 0.33 wt % slurry. Then, 1.2 g of the slurry was charged in aglass container, ultraviolet rays (1.65 mW/cm²) were irradiated for 90minutes, 1 g was then sampled and thereto, 2 mL of isopropyl alcohol, 2mL of hexane and 3 mL of distilled water were sequentially added. Themixture was stirred, 2-ethylhexyl p-methoxycinnamate was extracted inthe hexane phase, and the absorbance (at 300 nm) of the hexane phase wasmeasured to a light pass length of 1 mm by a spectrophotometer (UV-160,manufactured by Shimadzu Corporation). From the difference between theabsorbance decrease rate at 300 nm and the absorbance decrease rate in anull test (no addition of titanium oxide and zinc oxide), thedecomposition percentage of 2-ethylhexyl p-methoxycinnamate wascalculated. The results are shown in Table 4 below. TABLE 4Decomposition Rate % Production Example 1 0.5 Production Example 2 0.5Production Example 3 2.0 Production Example 4 0.5 ConventionalSurface-Treated Titanium 16.0 Oxide (MT-100T) ConventionalSurface-Treated Titanium 9.0 Oxide (TTO-S1) Uncoated Titanium Oxide(starting 80.0 material of Production Example 2) Uncoated Zinc Oxide(starting material 21.0 of Production Example 4)

[0160] The silica-coated titanium oxide and the silica-coated zinc oxidewhich can be used in the present invention had a decompositionpercentage of 5% or less in any substance, revealing that theultraviolet absorber decomposability was extremely low as compared withuncoated products and conventional surface-treated products.

Example 4

[0161] Measurement of Powder Kinetic Friction Coefficient, Glass PlateMethod:

[0162] The silica-coated titanium oxides obtained in Production Examples1 to 3, two kinds of respectively corresponding uncoated titaniumoxides, two kinds of conventional surface-treated titanium oxides(MT500SA produced by Teica Corp. and TTO-S1 produced by Ishihara SangyoKaisha, Ltd.), the silica-coated zinc oxide obtained in ProductionExample 4 and an uncoated zinc oxide were used as test substances andmeasured on the powder kinetic friction coefficient by a glass platemethod. More specifically, each test substance powder was dispersed on aglass plate of 100×200 mm to an amount of 10 mg/cm². This glass platewas placed on the test table of a surface property measuring apparatus(HEIDON-14DR manufactured by Shinto Kagaku K.K.) and the coefficient ofkinetic friction was measured under conditions such that the load was22.2 g/cm², the moving speed was 200 mm/min and the moving distance was20 mm. The results are shown in Table 5. TABLE 5 Coefficient of PowderKinetic Friction Production Example 1 0.441 Production Example 2 0.447Production Example 3 0.510 Production Example 4 0.490 ConventionalSurface-Treated 0.554 Titanium Oxide (MT500SA) ConventionalSurface-Treated 0.685 Titanium Oxide (TTO-S1) Uncoated Titanium Oxide(starting 0.584 material of Production Example 1) Uncoated TitaniumOxide (starting 0.641 material of Production Example 2) Uncoated ZincOxide (starting 0.640 material of Production Example 4)

[0163] The silica-coated titanium oxide and the silica-coated zinc oxidefor use in the present invention had a coefficient of kinetic frictionof 0.550 or less in any test substance, whereas uncoated products andconventional surface-treated products exhibited a value in excess of0.550.

Examples 5 to 7

[0164] W/O Sunscreen milky lotions each having a composition shown inTable 6 (expressed by mass % based on the entire amount of the cosmeticmaterial) were prepared by an ordinary method. In Examples 5 to 7 andComparative Examples 1 to 3, the titanium oxide used was thesilica-coated titanium oxide of Production Example 3 and the zinc oxidewas the silica-coated zinc oxide of Production Example 4. However,before use, each metal oxide was subjected to a treatment for renderingthe surface hydrophobic to 3% by mass of dimethylpolysiloxane so as toallow the silica-coated titanium oxide and silica-coated zinc oxide todisperse in the oil phase side of the W/O milky lotion (hereinafter,these hydrophobitized products are called a “silicone-treatedsilica-coated titanium oxide” or a “silicone-treated silica-coated zincoxide”). The thus-prepared formulation products were evaluated asfollows on the ultraviolet protection effect, the transparency at theapplication and the feeling on use after the application to skin.

[0165] <Evaluation of Ultraviolet Protection Effect>

[0166] SPF was measured under test conditions according to the standardsof SPF Measuring Method (JCIA method) provided by the Japan CosmeticIndustry Association (JCIA) in 1992.

[0167] PA was measured under test conditions according to the standardsof UVA Protection Effect Measuring Method provided by the Japan CosmeticIndustry Association in 1996.

[0168] <Evaluation of Transmittance at the Application: Glass PlateCoating Method>

[0169] A formulation product was coated on a glass plate to a coatedthickness of 10 μm and left standing at room temperature for 1 hour.Thereafter, the whiteness degree W value was measured by a colordifference meter (TC-8600, manufactured by Tokyo Denshoku) using a CIEcolor specification system with black paper (the black part of a hidingchart was used therefor) placed on the back.

[0170] <Evaluation of Feeling on Use after Application to Skin>

[0171] Each formulation product was applied to the inner arm part of 10professional panelists and rated ⊚ for the evaluation of good feeling by8 to 10 panelists, ◯ by 5 to 7 panelists, Δ by 2 to 4 panelists, or × by2 to 4 panelists. The results are shown together in Table 6. TABLE 6Ingredients Example Comparative Example (mass %) 5 6 7 1 2 3 Squalane5.0 5.0 5.0 5.0 5.0 5.0 Decamethyl- 12.0 12.0 12.0 12.0 12.0 12.0cyclopenta- siloxane Decaglyceryl 2.5 2.5 2.5 2.5 2.5 2.5 pentaoleateHexaglyceryl 0.3 0.3 0.3 0.3 0.3 0.3 polylisinolate Silicone-treated 6.03.75 3.75 15.0 7.5 — silica-coated titanium oxide Silicon-treated 9.011.25 11.25 — 7.5 15.0 silica-coated zinc oxide 2-Ethylhexyl p- 6.0 6.03.0 6.0 6.0 6.0 methoxy- cinnamate 4-tert-Butyl-4′- — — 2.0 — — —methoxydi- benzoyl- methane Magnesium 0.5 0.5 0.5 0.5 0.5 0.5 sulfateGlycerin 5.0 5.0 5.0 5.0 5.0 5.0 Paraben 0.2 0.2 0.2 0.2 0.2 0.2Purified water Balance Balance Balance Balance Balance Balance SPF 41.040.3 41.8 42.0 41.0 32.0 PFA 7.8 7.8 10.0 7.3 7.3 5.9 PA ++ ++ +++ ++ ++++ W (whiteness) 12.0 11.0 10.5 31.5 22.5 5.5 Feeling on use ⊚ ⊚ ⊚ ⊚ ⊚ ⊚

[0172] As is apparent from the results in Table 6, when the amount oftitanium oxide as expressed by the mass ratio of particulate titaniumoxide to particulate zinc oxide is 2:3 or more, the W value is as highas to exceed 20 and the unpleasant whitening is serious. Also, when theamount of titanium oxide as expressed by the mass ratio of particulatetitanium oxide to particulate zinc oxide is 1:5 or less, the capabilityof ultraviolet protection decreases despite good transparency at thetime of application. On the other hand, the products of the presentinvention as having a specific mass ratio of particulate titanium oxideto particulate zinc oxide, exhibits good transparency with a W value of15 or less while maintaining the same capability of ultravioletprotection as in the sole use of titanium oxide and at the same time,exhibits good use feeling. Furthermore, as is apparent from Examples 2and 3, the products of the present invention are free of decompositionof 2-ethylhexyl p-methoxycinnamate or4-tert-butyl-4′-methoxydibenzoylmethane and therefore, favored with highsafety and high stability.

Examples 8 to 10

[0173] W/O Sunscreen milky lotions each having a composition shown inTable 7 (expressed by mass % based on the entire amount of the cosmeticmaterial) were prepared by an ordinary method. In Examples 8 to 10 andComparative Examples 4 to 6, the titanium oxide used was thesilica-coated titanium oxide of Production Example 3 and the zinc oxideused was the silica-coated zinc oxide of Production Example 4. Theformulation products prepared were evaluated on the ultravioletprotection effect, the transparency at the application and the feelingon use after the application to skin in the same manner as in Examples 5to 7. TABLE 7 Ingredients Example Comparative Example (mass %) 8 9 10 45 6 Methylpoly- 10.0 10.0 10.0 10.0 10.0 10.0 siloxane Decamethyl- 25.025.0 25.0 25.0 25.0 25.0 cyclopenta- siloxane Polyether- 1.0 1.0 1.0 1.01.0 1.0 modified silicone Silicone-treated 6.0 3.75 3.75 15.0 7.5 —silica-coated titanium oxide Silicone-treated 9.0 11.25 11.25 — 7.5 15.0silica-coated zinc oxide 2-Ethylhexyl p- 6.0 6.0 3.0 6.0 6.0 6.0methoxy- cinnamate 4-tert-Butyl-4′- — — 2.0 — — — methoxydi- benzoyl-methane Glycerin 5.0 5.0 5.0 5.0 5.0 5.0 Purified water Balance BalanceBalance Balance Balance Balance SPF 42.0 41.0 43.0 43.0 41.0 31.0 PFA7.9 7.8 10.6 7.6 7.8 6.1 PA ++ ++ +++ ++ ++ ++ W (whiteness) 11.0 10.09.5 35.0 20.0 7.0 Feeling on use ⊚ ⊚ ⊚ ⊚ ⊚ ⊚

[0174] Similarly to Examples 5 to 7, when the amount of titanium oxideas expressed by the mass ratio of particulate titanium oxide toparticulate zinc oxide is 2:3 or more, the W value is as high as toexceed 20 and the unpleasant whitening is serious. Also, when the amountof titanium oxide as expressed by the mass ratio of particulate titaniumoxide to particulate zinc oxide is 1:5 or less, the capability ofultraviolet protection decreases despite good transparency at the timeof application. On the other hand, the products of the present inventionas having a specific mass ratio of particulate titanium oxide toparticulate zinc oxide, exhibits good transparency with a W value of 15or less while maintaining the same capability of ultraviolet protectionas in the sole use of titanium oxide and at the same time, exhibits gooduse feeling. Furthermore, as is apparent from Examples 2 and 3, theproducts of the present invention are free of decomposition of2-ethylhexyl p-methoxycinnamate or4-tert-butyl-4′-methoxydibenzoylmethane and therefore, favored with highsafety and high stability.

INDUSTRIAL APPLICABILITY

[0175] The cosmetic composition of the present invention has excellentultraviolet protection against both UVB and UVA, causes neitherunpleasant whitening to the applied skin nor skin irritation, andensures good feeling on use and high safety and high stability withoutcausing decomposition of the ingredients blended in the cosmeticmaterial, such as organic ultraviolet absorber. Therefore, the cosmeticcomposition of the present invention is particularly useful for use incosmetics having ultraviolet protection effect.

1. A cosmetic composition having blended therein silica-, alumina- oralumina/silica-coated particulate titanium oxide and silica-, alumina-or alumina/silica-coated particulate zinc oxide at a mass ratio of 1:4to 2:3, the particulate titanium oxide and the particulate zinc oxideeach having an average primary particle size of 0.01 to 0.2 μm.
 2. Thecosmetic composition as claimed in claim 1, which comprises the silica-,alumina- or alumina/silica-coated particulate titanium oxide and thesilica-, alumina- or alumina/silica-coated particulate zinc oxide intotal amount of 5 to 25% by mass based on the amount of the cosmeticcomposition.
 3. The cosmetic composition as claimed in claim 1, whichcomprises an organic ultraviolet absorber.
 4. The cosmetic compositionas claimed in claim 1, which comprises from 2 to 8% by mass of2-ethylhexyl p-methoxycinnamate.
 5. The cosmetic composition as claimedin claim 1, which comprises from 0.1 to 3% by mass of4-tert-butyl-4′-methoxydibenzoylmethane.
 6. The cosmetic composition asclaimed in claim 1, wherein the cosmetic composition maintains the sameSPF (Sun Protection Factor) value as in the sole use of titanium oxideand when said cosmetic composition is applied to a thickness of 10 μm,the whiteness W value measured using the CIE (International Commissionon Illumination) color specification system is 20 or less.
 7. Thecosmetic composition as claimed in claim 6, wherein the SPF (SunProtection Factor) value is 30 or more.
 8. The cosmetic composition asclaimed in claim 1, wherein the PFA (Protection Factor of UVA) of thecosmetic composition is 4 or more.
 9. The cosmetic composition asclaimed in claim 6, wherein the W value is 15 or less.
 10. The cosmeticcomposition as claimed in claim 1, wherein the particulate titaniumoxide and the particulate zinc oxide each is coated with silica and thesilica film has a thickness of 0.1 to 100 nm.
 11. The cosmeticcomposition as claimed in claim 10, wherein the surfaces of thesilica-coated particulate titanium oxide and zinc oxide are further madehydrophobic by using a hydrophobizing agent.
 12. The cosmeticcomposition as claimed in claim 11, wherein the hydrophobizing agent isone or more selected from the group consisting of silicone oils,alkoxysilanes, silane coupling agents, and higher fatty acid salts. 13.The cosmetic composition as claimed in claim 10, wherein thesilica-coated particulate titanium oxide and the silica-coatedparticulate zinc oxide each has a photocatalytic activity, determined bya tetralin auto-oxidation method, of 60 Pa/min or less.
 14. The cosmeticcomposition as claimed in claim 10, wherein the silica-coatedparticulate titanium oxide and the silica-coated particulate zinc oxideeach has a dye discoloration rate (ΔABS₄₉₀/hr), determined by a SunsetYellow method, of 0.1 or less.
 15. The cosmetic composition as claimedin claim 10, wherein the silica-coated particulate titanium oxide andthe silica-coated particulate zinc oxide each has an organic ultravioletabsorber decomposition rate (ΔABS₃₄₀/hr) determined by a Parsol 1789method, of 0.02 or less.
 16. The cosmetic composition as claimed inclaim 10, wherein the silica-coated particulate titanium oxide and thesilica-coated particulate zinc oxide each has an organic ultravioletabsorber decomposition percentage, determined by an ethylhexylp-methoxycinnamate method, of 5% or less.
 17. The cosmetic compositionas claimed in claim 10, wherein the silica-coated particulate titaniumoxide and the silica-coated particulate zinc oxide each has a kineticfriction coefficient, determined by a glass plate method, of 0.550 orless.
 18. A method for producing a cosmetic composition, comprisingbringing particulate titanium oxide and particulate zinc oxide eachhaving an average primary particle size of 0.01 to 0.2 μm as a mixture(at a mass ratio of 1:4 to 2:3) or separately into contact with a silicafilm-forming composition containing water, an alkali, an organic solventand a silicic acid having neither an organic group nor a halogen or aprecursor capable of producing said silicic acid, with the water/organicsolvent ratio being from 0.1 to 10 and the silicic acid concentrationbeing from 0.0001 to 5 mol/liter, thereby coating the particulatetitanium oxide and the particulate zinc oxide with silica, and dryingand blending these particles.
 19. The method for producing a cosmeticcomposition as claimed in claim 18, which comprises blending from 2 to8% by mass of 2-ethylhexyl p-methoxycinnamate.
 20. The method forproducing a cosmetic composition as claimed in claim 18, which comprisesblending from 0.1 to 3% by mass of4-tert-butyl-4′-methoxydibenzoylmethane.
 21. An ultraviolet-protectingcosmetic material comprising the cosmetic composition claimed in any oneof claims 1 to
 17. 22. The ultraviolet-protecting cosmetic material asclaimed in claim 21, which is a W/O or O/W milky lotion, a cream, afoundation or a jell.